For example, it is well known in the current art to build spatial light modulators (SLM) of a micro mirror type U.S. Pat. No. 4,566,935, U.S. Pat. No. 4,710,732, U.S. Pat. No. 4,956,619. In general two main principles for building integrated devices, such as micromirror SLM, have been employed.
An integrated circuit (IC) is manufactured to a finished state, and then the micro mirrors are manufactured on said IC. The micro mirrors are built onto the IC wafers. An advantage with this approach is that, so called, IC foundries can be used, which presents a very cost efficient manufacturing of the electronics wafers. A disadvantage is that there is a very restricted selection of materials and methods that are usable for the manufacturing of the micromirrors, because there is an upper temperature limit of about 400° C., above which the electronics will be damaged. This makes the manufacturing of micromirrors having optimal performance more difficult.
Another way of building micromirror SLMs is at the end of the process for making the IC, micromirror manufacture is started on the same wafers. The advantage with this approach is that there is a greater freedom of selecting materials, methods and temperatures for the manufacture of micromirrors having good performance. A disadvantage is that the IC wafers cannot be manufactured in standard IC foundries, because the latter have very strict demands on a process of manufacturing to be standardized in order to be able to maintain the quality in the process.
Therefore, there is a need in the art for an improved method for manufacturing micro electric/mechanical/optical integrated devices.